Railway signaling apparatus



L. E. SPRAY RAILWAY SIGNALING APPARATUS Filed 001:. 9; 1922 F IE 1.

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INVENTOR 9C. flkF mac- Patented Feb. 10, 1925.

UNITED STATES PATENT FFIQE.

LESTER E. SlPRAY, 0E WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE 'UNIQN SWITCH & SIGNAL COMPANY, 05 SWISSVALE, FENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILVTAY SIGNALING APPARATUS.

Application filed Gotcber 9, 1922.

To all whom it may concern:

Be it known that I, Lns'rnn E. Srnnr, a citizen of the United States, residing at Wilkinshurg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway Signaling Apparatus, of which the following is a specification.

My invention relates to railway signaling apparatus.

One feature of my invention is the pro vision of means for reducing the variation in voltage applied to track relays.

I will describe three forms of signaling apparatus embodying my invention and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig 1 is a view showing diagrammatically one arrangement of signaling apparatus embodying my invention. Fig. 2 is a view showing a modification of the arrangement of apparatus shown in Fig. 1 and also embodying my invention. Fig. 3 is a view showing still another modification of the apparatus shown in Fig. 1 and also embodying my in vention.

Similar reference characters refer to similar parts in each of the three views.

Referring first to Fig. 1, the reference character A designates the rails of a portion of railway track divided by insulated joints 2 to form a block section C-D. A track transformer H, provided with a primary winding H and a secondary winding H supplies energy to this track section at one end O. The primary winding H is energized from a generator K through the line wires J. Connected across the rails A at the other end D of this section is a track relay R which controls certain signal apparatus not necessary to the complete disclosure of my invention and omitted from the drawings for the sake of simplicity.

Interposed between the upper track rail A and the relay R is a conductor E having a high positive temperature coefiicient. This conductor tends to eliminate voltage fluctuations at the relay due, for example to fluctuations in the voltage applied to the rails by the transformer H or to change in the resistance of the track ballast. Thus if the voltage across the rails at the relay end of the section rises, the increased voltage at Serial No. 593,234.

the relay tends to send a larger current through it, but this current heats the c011- ductor E, and due to the high positive temperature coefficient, this heating results in a considerable increase in resistance and a correspondingly larger voltage drop in this conductor thus tending to keep constant the voltage at the relay terminals.

The apparatus shown in Fig. 2 is the same as that shown in Fig. 1 except that an auxiliary heating element G of comparatively high resistance is connected across the rails at D, as shown, in multiple with the series circuit comprising the conductor E and the windings of the track relay. This heating element and the conductor E are so located that the latter is exposed to variations in the temperature of the former. Now if the voltage across the rails rises, the resulting increase in the current through the conductor E raises the temperature of that element and operates, as in Fig. 1, to stabilize the variations in voltage applied to the relay. But the increased voltage also increases the current through the heating element G and consequently raises its temperature and the temperature of the conductor E. This further increases the resistance of the said conductor E and hence emphasizes the regulating characteristics of the apparatus. In some cases better results may be obtained by making the heating element G of some material having thermo-electrical characteristics similar to the conductor E.

In Fig. 3, I show precisely the same apparatus as in Fig. 2 except that in this case the voltage regulating apparatus is connected at some distance from the relay, preferably about the middle of the section C-D. In this case however one of the rails A is provided with an insulating joint L. The heating element G is connected across the two rails on the transformer side of this joint, whereas the conductor E is connected across the joint itself. The operation of the apparatus is the same as the operation of the apparatus shown in Fig. 2. As was the case in Fig. 2, better results may be obtained in some cases by making the heating element G of some material having thermo-electrical characteristics similar to those of the conductor E.

Although I have herein shown and described only three forms of railway signal ing apparatus embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims Without departing from the spirit and scope of my invention.

aving thus described my invention, What I claim is:

1. Railway signaling apparatus comprising a track circuit, a conductor included in series in said circuit and having a positive temperature coefficient, and means connected across the rails 01' said circuit or heating said conductor.

2. Railway signaling apparatus compris: ing a track circuit provided With a track relay, aconductor interposed between one track rail and said relay and having a positive temperature coefiicient, and means connected across the rails of said circuit for heating said conductor.

3. Railway signaling apparatus comprising a track circuit,- a heating element connected across the rails of said circuit and having a positive temperature coeiiicient, and a conductor included in series in said circuit and subjected to heat from said element and also having a positive temperature coeflicient.

ture.

LEQIE k E. SPRAY. 

